Battery Pack System

ABSTRACT

An improved battery pack and system including such battery pack is disclosed. The battery pack includes a power control module positioned to allow for increased battery power or reduced battery pack size.

TECHNICAL FIELD

The described embodiments relate generally to a battery pack system.More particularly, the present embodiments relate to improvements inpackaging lithium-ion battery packs used in electronic devices to reducethe battery pack size and to improve system performance.

BACKGROUND

Recent advances in portable computing have utilized lithium-ionbatteries to provide power to laptops computers, portable media players,personal digital assistants (PDAs), cell phones, tablets and otherelectronic equipment. Lithium-ion batteries are favored because, poundfor pound, they are some of the most energetic rechargeable batteriesavailable. They have a number of important advantages over competingtechnologies. They are generally much lighter than other types ofrechargeable batteries of the same size because the electrodes of alithium-ion battery are made of lightweight lithium and carbon.

In addition to consumer electronics, lithium-ion batteries are alsopopular for use in military, electric vehicle and aerospaceapplications. Lithium-ion batteries may be used in place of lead acidbatteries in golf carts and utility vehicles. Lithium-ion batteriesprovide similar voltage levels as lead acid batteries so no modificationof the vehicle's drive system is needed. The batteries could also beused for electric tools, medical equipment and other uses.

Lithium is a highly reactive element, meaning that a lot of energy canbe stored in its atomic bonds. This translates into a very high energydensity for lithium-ion batteries. For example, a typical lithium-ionbattery can store 150 watt-hours of electricity in 1 kilogram ofbattery. A NiMH (nickel-metal hydride) battery pack can store perhaps100 watt-hours per kilogram, although 60 to 70 watt-hours might be moretypical. A lead-acid battery can store only 25 watt-hours per kilogram.Using lead-acid technology, it takes 6 kilograms to store the sameamount of energy that a 1 kilogram lithium-ion battery can handle. Forlightweight electronic devices, this is a significant advantage.

In addition to being lightweight, a lithium-ion battery pack may loseonly about 5 percent of its charge per month, compared to a 20 percentloss per month for NiMH batteries. Lithium-ion battery packs have nomemory effect, which means that a user does not have to completelydischarge them before recharging, as with some other battery types.Lithium-ion batteries can also be recharged hundreds of times whileother battery types may have more limited useful lives.

While lithium-ion batteries have many positive advantages, there aresome disadvantages also. For example, lithium-ion battery packs requirethat a protection circuit be included to maintain voltage and currentwithin safe limits. It is possible that failure of the battery pack dueto overheating could cause harm to the accompanying electronic device,possibly even melting the device housing in certain instances. In orderto avoid such situations, a protection circuit is generally included ina lithium-ion battery pack. Built into each pack, the protection circuitlimits the peak voltage of each cell during charge and prevents the cellvoltage from dropping too low on discharge. In addition, the celltemperature is monitored to prevent temperature extremes. With theseprecautions in place, the possibility of metallic lithium platingoccurring due to overcharge may be greatly reduced.

However, while the protection circuits are included for safety reasonsthey tend to make the battery packs relatively more expensive and theinclusion of protection circuits make the battery pack larger than itwould otherwise be. This increase in size may ameliorate some of theadvantages discussed above as electronic devices become increasinglysmaller and more compact.

A jelly roll design is the design used in many rechargeable batteries,and often for those batteries used in portable electronic devices. Inthis design, an insulating sheet is laid down, then a thin layer of ananode material is laid down, a separator layer is applied, and a cathodematerial is layered on top. This sandwich is then rolled up and insertedinto a hollow casing. The battery, once wrapped, may be sealed in aflexible container. The container may have a tail or seam where theflexible material seals to itself in order to encompass the battery.Electrodes may extend through the tail in order to provide an electricalconnection between the battery and internal components. The electrodesmay exit the flexible container, bend, and be electrically connected tovarious components as desired.

Therefore, it would be desirable to have a battery pack for anelectronic device which is more compact, while still including thesafety features associated with a protection circuit built into thebattery pack

SUMMARY

A battery pack includes a power control module to protect the batteryfrom being overcharged or improperly discharged. The power controlmodule is located on the battery pack in a location that permits thespace for the battery portion itself to be utilized to maximumefficiency. By locating the power control module on the side of thebattery pack housing opposite to the battery portion, improved overallpower performance of the system may be achieved. In some embodiments,increased battery performance and power may be achieved withoutincreasing the overall size of the battery pack. In another embodimentthe overall battery pack size may be reduced while maintaining the samepower performance as with the conventionally sized battery pack.

A system including an electronic device which utilizes variousembodiments of the battery back is disclosed. The electronic device maybe a laptop computer, tablet, smartphone or the like and the power needsof the device may be met in a more efficient manner utilizing disclosedembodiments. The battery pack may be made smaller thus reducing theamount of space which must be allocated in the electronic device for thebattery pack. In another embodiment, increased battery size may beachieved while maintain the size of the allocated space for the batterypack. By reducing required space or increasing the amount of powersupplied to the electronic device from the battery pack for a givensize, improved efficiency and performance as well as increasedconvenience to a user of the electronic device may be achieved withdisclosed embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1 shows a perspective view of an electronic device;

FIG. 2 shows the underside of an electronic device;

FIG. 3 shows a side view of a conventional battery pack;

FIG. 4 shows a side cutaway view of an electronic device including aconventional battery pack;

FIG. 5 shows a side view of a battery pack in accordance with oneembodiment;

FIG. 6 shows a side cutaway view of an electronic device including abattery pack in accordance with one embodiment;

FIG. 7 shows a side view of a battery pack in accordance with anotherembodiment;

FIG. 8 shows a side cutaway view of an electronic device including abattery pack in accordance with another embodiment;

FIG. 9 shows a perspective view of a conventional battery pack housing;

FIG. 10 shows a perspective view of a battery pack housing in accordancewith one embodiment;

FIG. 11 shows a perspective view of a battery pack housing in accordancewith another embodiment; and

FIG. 12 shows a flow chart illustrating a method for making a batterypack.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodimentsillustrated in the accompanying drawings. It should be understood thatthe following descriptions are not intended to limit the embodiments toone preferred embodiment. To the contrary, it is intended to coveralternatives, modifications, and equivalents as can be included withinthe spirit and scope of the described embodiments as defined by theappended claims.

The following disclosure relates to a battery pack which may be used inconjunction with an electronic device such as a laptop computer,portable media player, personal digital assistant (PDA), cell phone,tablet or other electronic equipment. In a particular embodiment, thebattery pack includes a lithium-ion battery and a power control moduleor safety circuit which is included to maintain voltage and currentwithin safe limits. Built into each pack, the protection circuit limitsthe peak voltage of each cell during charge and prevents the cellvoltage from dropping too low on discharge. In addition, the celltemperature may be monitored to prevent temperature extremes which coulddamage the battery or the electronic device.

These and other embodiments are discussed below with reference to FIGS.1-7. However, those skilled in the art will readily appreciate that thedetailed description given herein with respect to these Figures is forexplanatory purposes only and should not be construed as limiting.

FIG. 1 illustrates a laptop computer 11 which may include a screen 12and a keyboard 13 as well as a mouse pad 14. Laptop computer 11 may alsoinclude a battery pack (not shown) which is generally located on theunderside 15 of laptop computer 11. The battery pack is used to providepower to laptop computer 11 and its electronic components. As statedabove, the electronic device in this embodiment could also be a portablemedia player, cell phone, or other device.

Referring to FIG. 2, the underside 15 of laptop computer 11 is shownwhich includes a battery pack 16 inserted into a compartment 17 in theunderside 15 of laptop computer 11. Battery pack 16 may beelectromagnetically connected to the main logic board (not shown) andother electronic circuit board or components.

Referring to FIG. 3, a side view of a conventional battery pack 16 isshown. Battery pack 16 includes battery portion 19, a power controlmodule 23 and an electrode attachment portion 20 which attacheselectrode 21 to battery portion 19. Power control module 23 is shownmounted adjacent to battery portion 19 and electrode attachment portion20. Depending upon the size and power rating of battery portion 19,battery portion 19 has a length of B1. Power control module 23 also hasa dimension of length PCM 1. This configuration results in an overalllength of battery pack 16 of L1 which is B1+PCM1=L1. L1 is theapproximate length of compartment 17 in electronic device 11 as shownand described in FIG. 4 below.

The power control module 23 shown in FIG. 3 is included for safetyreasons as described above. That is, in certain battery types, such aslithium-ion batteries, it is important to control the charge anddischarge rate of the lithium-ion battery to prevent inadvertent failureof the battery portion 19 which could damage electronic device 11 and/orits electronic circuitry 22. In addition, as discussed above, powercontrol module 23 may monitor the temperature of battery portion 19 inorder to prevent inadvertent overheating of battery portion 19 whichcould result in failure of battery portion 19.

Referring to FIG. 4, a cutaway side view of electronic device 11includes a housing 18. Housing 18 includes a compartment 17 whichcontains battery pack 16 described above with respect to FIG. 3. Batterypack 16 includes a battery 19 which is connected through electrodeconnection 20 to electrode 21. Electrode 21 connects battery pack 16 toa main logic or circuit board 22. In this conventional battery pack, apower control module 23 is included in battery pack 16 and is positionedadjacent to electrode attachment portion 20, electrode 21 and batteryportion 19 above the main logic board 22 and other electroniccomponents. Battery portion 19 may be a lithium-ion battery or otherbattery type. Compartment 17 in housing 18 is defined by a width(measured from above and not shown), depth (D1) and length (L1) which issized to allow insertion and removal of battery pack 16 as will bediscussed in more detail below. That is, a cover portion 24 in underside15 of electronic device 11 may be opened to allow access to battery pack16. Battery pack 16 may be removed by a user and replaced or rechargedas needed.

Referring to FIG. 5, a side view of an embodiment of a battery pack 24is shown which includes power control module 23 mounted below electrode21. By locating power control module 23 below electrode 21, batteryportion 19 may be made larger with a length of B2 as shown in FIG. 5while still maintain an overall length for battery pack 24 of L1. Bymaking battery portion 19 larger, an increase in power may be achieved.That is more space may be provided for the three primary functionalcomponents of a lithium-ion battery: the positive and negativeelectrodes; and the electrolyte. The overall length L1 of battery pack24 remains the same as with battery pack 16 described above such thatbattery pack 24 may fit into compartment 17 in electronic device 11 asdescribed above but the increased power increases the usefulness ofelectronic device 11 by enabling more capabilities.

Referring to FIG. 6, the battery pack 16 of FIG. 5 is shown in a cutawayview of compartment 17 of electronic device 11. The overall length ofbattery pack 16 is L1 as was the case with the conventional battery pack16 shown in FIG. 4. Power control module 23 is shown mounted belowelectrode attachment portion 21 as described above with respect to FIG.5. Thus, in this embodiment, battery portion 19 may be made largerresulting in more power to electronic device 11 and/or longer batterylife between recharging of battery portion 19. That is, battery portion19 has a length B2 as described above with respect to FIG. 5. Thus,while the overall length L1 of battery pack 24 is the same as that ofconventional battery pack 16 in FIG. 4, the larger battery portionlength B2 results in additional amount of battery power which may bedelivered to electronic device 11 which can result in improvedperformance and enabling additional capabilities.

Referring to FIG. 7, another embodiment of a battery pack is shown. Inthis embodiment, a battery pack 25 includes a battery portion 19 whichincludes a length B1 as was shown in the embodiment described in FIGS. 3and. 4. However, because power control module 23 is located on theunderside of electrode attachment portion 21, the overall length ofbattery pack 25 is L2 which is less than length L1 of the battery packsdescribed in FIGS. 3 and 4. Thus battery pack 25 has the same batterypower level as battery pack 16 shown in FIGS. 3 and 4 because it has thesame sized battery portion 19. However, battery pack 25 has a length L2that is less than length L1 of battery pack 16 and thus may allow areduction in the size of electronic device 11. As the size of electronicdevices continues to decrease, reducing the size of a battery pack whilemaintaining the same power capabilities may be significant.

Referring to FIG. 8, the battery pack 25 of FIG. 7 is shown in acompartment 26 of electronic device 11. The overall length of batterypack 25 is L2 as shown in FIG. 7 which is less than the length L1 of thebattery pack shown in FIG. 3. Power control module 23 is shown mountedbelow electrode 21 as described above with respect to FIG. 7. In thisembodiment, battery portion 19 has a length B1 as described above inFIG. 7 and FIG. 3. This means that battery pack 25 may provide the samepower performance as battery pack 19 shown in FIG. 3. However, becausethe length L2 of battery pack 25 is less than the length L1 of batterypack 16, the length of compartment 26 may be smaller than the length ofcompartment 17 in FIGS. 4 and 6. Thus, the same battery power level canbe provided to electronic device 11 as with the battery pack 16 of FIGS.3 and 4 but, because the length L2 of compartment 26 in FIG. 7 is lessthan length L1 of compartment 17 in FIG. 4, the size of electronicdevice may either be reduced or, if the size of electronic device ismaintained, additional components may be added resulting in increasedperformance or convenience to a user.

Referring to FIG. 9, a perspective view of a housing for conventionalbattery pack 16 is shown. Housing 27 is a tray like structure thatcontains the battery portion (not shown) adjacent upper surface 28. Thelength B1 of tray in housing 27 is sufficient to contain the batteryportion of a size having a particular power capability. In thisconventional battery pack, housing 27 has power control module 23located adjacent to electrode portion 21 and upper surface 28. A mainlogic board or other circuitry may connect to electrode portion 21 atflexible attachment point 31 on lower surface 29. Battery pack 16 has anoverall length of L1 as shown.

Referring to FIG. 10, a perspective view of an embodiment is shownincluding housing 27 as described in FIG. 9 above. That is, a powersource, which may be a battery portion is contained on the upper surface28 of housing 27 and an electrode 21 is connected to the power source.In this embodiment, power control module 23 is moved adjacent toelectrode portion 21 and lower surface 29. Flexible attachment point 31may be extended as necessary or desirable to provide sufficientconnection to main logic board or other circuitry (not shown). By movingpower control module 23 to this location adjacent lower surface 29, theamount of space to contain battery portion (not shown) is increased fromthat shown in FIG. 9. That is, the length B2 of the space to containbattery portion 19 is increased from length B1 shown in FIG. 9. Thus, alarger battery portion 19 having higher power capability may be includedin housing 27 without increasing the overall length L1 of the batterypack which remains the same as L1 in FIG. 9.

Referring to FIG. 11, an alternate embodiment of a battery pack isshown. In this embodiment, power control module 23 is moved adjacent toflexible attachment point 31 on electrode portion 21 as is describedabove with respect to FIG. 10. As with the embodiment shown in FIG. 10attachment point 31 may be extended as necessary or desirable to providesufficient connection to main logic board or other circuitry (notshown). In the embodiment shown in FIG. 11, however, housing 27 has beenshortened such that the overall length L2 of the battery pack is lessthan length L1 of the battery pack described in FIGS. 9 and 10. Thelength B1 of the tray portion in housing 27 is maintained as in FIG. 9such that the same sized battery portion as is used in FIG. 9 may beincluded in this embodiment. Thus a more compact battery pack having ashorter overall length L2 may be used to provide power to electronicdevice 11 without reducing the amount of such provided power. With thisembodiment, either the overall size of electronic device could bereduced, or additional components could be added to electronic device 11without increasing the overall size of electronic device 11. That is,the size of battery compartment 17 in FIG. 2 could be reduced withoutsacrificing power capabilities or device performance. By addingadditional components to the freed space, improved performance and/orincreased convenience to a user of electronic device 11 may beaccomplished. Similarly, reducing the size of electronic device 11 wouldalso result in increased convenience to a user of the device.

As discussed above, (for example with respect to FIG. 4) bothconventional battery packs and embodiments of battery packs disclosedherein may be inserted into and removed from electronic devices such aslaptop computers. The battery packs may then be replaced, recharged orrepaired as needed. The embodiments disclosed herein do not add anycomplexity to this removal process but do allow for increased efficiencyor reduction in size of the device as discussed above. The absoluteamount of reduction in size from, for example, L1 to L2, is provided forillustrative purposes only. It is the relocation of power control module23 to a bottom surface of the battery pack that permits the increasedefficiency or reduced size. The electrodes 21 on the battery packs mayinterface with electrical connections such as the main logic boards andother electronic circuitry. While lithium-ion batteries have beendiscussed as the power source in battery portions 19 and 25, it can beappreciated that embodiments described herein could be employed withbattery portions employing other battery chemistries which utilize powercontrol modules to control battery pack functionality for safety andefficiency improvements.

Referring to FIG. 12, a flow chart for a method of making a battery packis shown. In step 32, a housing having an upper and a lower surface isprovided. In step 33, a power source is contained adjacent to the uppersurface in the housing. An electrode is connected to the power source instep 34. A power control module is attached adjacent to the lowersurface of the housing in step 35. The power source may be a lithium-ionbattery and the power control module is attached adjacent the lowersurface such that it is contained with a battery pack length defined bythe battery portion and the attached electrode.

It can be appreciated from the above description that moving powercontrol module 23 on a lithium-ion or other battery type, may result inimproved efficiencies to battery packs and to the electronic or otherdevices that utilize them. By improving such efficiencies, greaterperformance and convenience may be provided to a user of electronicdevices. However, embodiments disclosed herein could be used in otherthan electronic devices. For example, electric powered automobiles orother electric powered forms of transportation such as utility vehiclesutilize battery packs and may benefit from implementation of theembodiments disclosed herein. In addition, electric tools, medicalequipment and other uses may benefit from these embodiments.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of the specificembodiments described herein are presented for purposes of illustrationand description. They are not target to be exhaustive or to limit theembodiments to the precise forms disclosed. It will be apparent to oneof ordinary skill in the art that many modifications and variations arepossible in view of the above teachings.

What is claimed is:
 1. A battery pack, comprising: a housing includingan upper surface and a lower surface; a battery portion adjacent saidupper surface; an electrode portion connected to said battery portion,said electrode portion extending adjacent said lower surface; and apower control module adjacent said lower surface.
 2. The battery pack ofclaim 1 wherein said battery portion is a lithium-ion battery.
 3. Thebattery pack of claim 1 wherein said battery portion and said electrodeportion define a first length of said battery pack.
 4. The battery packof claim 3 wherein said power control module is included within saidfirst length.
 5. The battery pack of claim 3 wherein said batteryportion has a battery power level.
 6. The battery pack of claim 5wherein said battery power level remains the same and the batteryportion and the electrode portion define a second length which is lessthan the first length.
 7. The battery pack of claim 3 wherein said firstlength is less than a third length defined by said power control modulemounted adjacent said upper surface.
 8. The battery pack of claim 7wherein said battery portion and said electrode portion define saidfirst length and said battery portion includes a battery power levelmore than said battery power level of said battery portion in said thirdlength and wherein said first length and said third length areapproximately equal.
 9. An electronic device comprising: a main logicboard; a battery pack electromagnetically connected to said main logicboard, said battery pack including: a housing having an upper and alower surface; a power source contained adjacent said upper surface; anda power control module adjacent to said lower surface.
 10. Theelectronic device of claim 9 wherein said electronic device includes alaptop computer.
 11. The electronic device of claim 9 wherein saidelectronic device includes a portable media player.
 12. The battery packof claim 9 wherein said power source is a lithium-ion battery.
 13. Thebattery pack of claim 9 wherein said power source and an electrodeportion define a first length of said battery pack.
 14. The battery packof claim 13 wherein said power control module is included within saidfirst length.
 15. The battery pack of claim 13 wherein said power sourcehas a battery power level.
 16. The battery pack of claim 15 wherein saidbattery power level remains the same and the power source and theelectrode portion define a second length which is less than the firstlength.
 17. The battery pack of claim 13 wherein said first length isless than a third length defined by said power control module mountedadjacent said upper surface.
 18. The battery pack of claim 17 whereinsaid power source and said electrode portion define said first lengthand said power source includes a battery power level more than saidbattery power level of said power source in said third length andwherein said first length and said third length are approximately equal.19. A method for making a battery pack comprising the steps of:providing a housing having an upper and a lower surface; containing apower source adjacent said upper surface; connecting an electrode tosaid power source; and providing a power control module adjacent to saidlower surface.
 20. The method of claim 19 wherein said power sourceincludes a lithium-ion battery.